How Long Does Stem Ginger Keep For?

Hi guys! Hope you all had a good Christmas and new year!

I'm usually incredibly cautious with food safety, but it's bit of a resolution to be less of a neurotic basket case when it comes to stuff like this. So, I'm making gingerbread flapjacks next week and will be using stem ginger. The jar says once opened use within 4 weeks and I've had it (refrigerated) for double that. Will it be ok? My first instinct is to throw it out but then stuff like Ketchup normally says use within 4 weeks and I know no one sticks to that.